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Pradeep K. Sengupta

Bio: Pradeep K. Sengupta is an academic researcher from University of Calcutta. The author has contributed to research in topics: Fluorescence anisotropy & 3-Hydroxyflavone. The author has an hindex of 29, co-authored 66 publications receiving 2962 citations. Previous affiliations of Pradeep K. Sengupta include Florida State University & University of Michigan.


Papers
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Journal ArticleDOI
TL;DR: In this article, the double minimum hydrogen-bonding potential of 3-hydroxyflavone and quercetin at room temperature in solution has been used to explain the luminescence of these molecules at 77 K in 2-methylbutane rigid matrix.

561 citations

Journal ArticleDOI
TL;DR: It is demonstrated that binding of the flavonoids to the RBC membranes significantly inhibits lipid peroxidation, and at the same time enhances their integrity against hypotonic lysis.

258 citations

Journal ArticleDOI
TL;DR: The emission, excitation, and anisotropy data indicate that the quercetin molecules bind at a motionally restricted site near tryptophan-214 in the interdomain cleft region of HSA, and the excitation spectrum suggests occurrence of efficient Förster type resonance energy transfer (FRET) from the single tryptophile residue of H SA to the protein bound quercETin.

201 citations

Journal ArticleDOI
01 May 2001-Proteins
TL;DR: Analysis of relevant spectroscopic data leads to the conclusions that two binding sites are involved in BSA–3HF interaction, and the interaction is slightly positively cooperative in nature with a similar binding constant.
Abstract: Recent studies have shown that various synthetic as well as therapeutically active naturally occurring flavonols possess novel luminescence properties that can potentially serve as highly sensitive monitors of their microenvironments in biologically relevant systems. We report a study on the interactions of bovine serum albumin (BSA) with the model flavonol 3-hydroxyflavone (3HF), using the excited-state proton-transfer (ESPT) luminescence of 3HF as a probe. Upon addition of BSA to the flavonoid solutions, we observe remarkable changes in the absorption, ESPT fluorescence emission and excitation profiles as well as anisotropy (r) values. Complexation of 3HF with protein results in a pronounced shift (20 nm) of the ESPT emission maximum of the probe (from lambda(max)(em) = 513 nm to lambda(max)(em) = 533 nm) accompanied by a significant increase in fluorescence intensity. The spectral data also suggest that, in addition to ESPT, the protein environment induces proton abstraction from 3HF leading to formation of anionic species in the ground state. Fairly high values of anisotropy are observed in the presence of BSA for the tautomer (r = 0.25) as well as anion (r = 0.35) species of 3HF, implying that both the species are located in motion-restricted environments of BSA molecules. Analysis of relevant spectroscopic data leads to the conclusions that two binding sites are involved in BSA-3HF interaction, and the interaction is slightly positively cooperative in nature with a similar binding constant of 1.1 - 1.3 x 10(5) M(-1) for both these sites. Proteins 2001;43:75-81.

163 citations

Journal ArticleDOI
TL;DR: The novel use of the intrinsic fluorescence characteristics of the plant flavonoid fisetin (3,3′,4′,7‐OH flavone) to explore its binding and site(s) of solubilisation in egg lecithin liposomal membranes is demonstrated.

115 citations


Cited by
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Journal ArticleDOI
TL;DR: This review discusses the application of infrared spectroscopy to the study of proteins by focusing on the mid-infrared spectral region and theStudy of protein reactions by reaction-induced infrared difference spectroscopic.

3,596 citations

Book ChapterDOI
TL;DR: The aim of this chapter is to present recent developments in the vibrational spectroscopy of peptides, polypeptides, and proteins.
Abstract: Publisher Summary The vibrational spectrum of a molecule is determined by its three-dimensional structure and its vibrational force field. An analysis of this (usually infrared (IR) and Raman) spectrum can therefore provide information on the structure and on intramolecular and intermolecular interactions. The more probing the analysis, the more detailed is the information that can be obtained. Detailed analyses of the vibrational spectra of macromolecules, however, have provided a deeper understanding of structure and interactions in these systems. An important advance in this direction for proteins came with the determination of the normal modes of vibration of the peptide group in N-methylacetamide, and the characterization of several specific amide vibrations in polypeptide systems. Extensive use has been made of spectra-structure correlations based on some of these amide modes, including attempts to determine secondary structure composition in proteins. Polypeptide molecules exhibit many more vibrational frequencies than the amide modes. Over the years, some normal-mode calculations have provided greater insight into the spectra of particular molecules. However, these have often been based on approximate structures or have employed limited force fields. These force fields can now serve as a basis for detailed analyses of spectral and structural questions in other polypeptide molecules. The aim of this chapter is to present these recent developments in the vibrational spectroscopy of peptides, polypeptides, and proteins.

2,640 citations

Journal ArticleDOI
TL;DR: Theoretical Methodologies and Simulation Tools, and Poisson−Boltzmann Theory, and Phenomenology of Transport inProton-Conducting Materials for Fuel-CellApplications46664.2.1.
Abstract: 1. Introduction 46372. Theoretical Methodologies and Simulation Tools 46402.1. Ab Initio Quantum Chemistry 46412.2. Molecular Dynamics 46422.2.1. Classical Molecular Dynamics and MonteCarlo Simulations46432.2.2. Empirical Valence Bond Models 46442.2.3. Ab Initio Molecular Dynamics (AIMD) 46452.3. Poisson−Boltzmann Theory 46452.4. Nonequilibrium Statistical Mechanical IonTransport Modeling46462.5. Dielectric Saturation 46473. Transport Mechanisms 46483.1. Proton Conduction Mechanisms 46483.1.1. Homogeneous Media 46483.1.2. Heterogeneous Systems (ConfinementEffects)46553.2. Mechanisms of Parasitic Transport 46613.2.1. Solvated Acidic Polymers 46613.2.2. Oxides 46654. Phenomenology of Transport inProton-Conducting Materials for Fuel-CellApplications46664.1. Hydrated Acidic Polymers 46664.2. PBI−H

1,915 citations

Journal ArticleDOI
TL;DR: This review deals with current concepts of vibrational spectroscopy for the investigation of protein structure and function, namely the amide I vibration of the polypeptide backbone that is used for secondary-structure analysis and some of the general aspects also apply to RamanSpectroscopy.
Abstract: This review deals with current concepts of vibrational spectroscopy for the investigation of protein structure and function. While the focus is on infrared (IR) spectroscopy, some of the general aspects also apply to Raman spectroscopy. Special emphasis is on the amide I vibration of the polypeptide backbone that is used for secondary-structure analysis. Theoretical as well as experimental aspects are covered including transition dipole coupling. Further topics are discussed, namely the absorption of amino-acid side-chains, 1H/2H exchange to study the conformational flexibility and reaction-induced difference spectroscopy for the investigation of reaction mechanisms with a focus on interpretation tools.

1,753 citations